Time and again, I find hot debates on what’s the best pool filter system with regards to sand filters vs cartridge filters. There seems to be no clear winner between the two and the matter escalates further with the mention of DE filters; another popular type of pool filter.

For pool owners, it’s not a matter of knowing the right pool filter type only, it goes beyond and requires you to buy the best pool filter.

But then, how do you know the best type of filter for your pool? What are some of the factors to consider when buying pool filters? Also, what are some of the best sand filters and cartridge filters?All these and more are factors that you need to understand so that you make the most informed buying decision.

I have worked in the pool industry for a while and being a swimming enthusiast, I have a pool in my backyard. I have used several types of pool filters and today, here are my top picks for the best pool filters in the market.

View on AmazonThough not best for large pools, it offers value for money because it has integrated the pump and filter.

When you buy this pool filter, you don’t have to buy a pump again. Retailing at around $130, the Krystal Clear boasts a steady 2,100 GPH flow rate making it suitable for 16’ to 24’ above ground pools. I’ve used this with several pools including Intex Ultra Frame and Coleman Power Steel and the result was clean crystal clear water.

One thing I like about it is the convenience. First, it allows pool owners to do more; the 6-function valveallows filtering, backwashing, rinsing, recirculation, draining and closing the system.

Remember to check the local regulations on filter backwashing and this one needs frequent backwashing.

In addition to this, Intex built this filter pump with a 24-hour timer to allow you concentrate on other stuff.

But then, the GPH is very low and this is not the best with sand filters so, at times, it will be ineffective especially with very small particles, 20 microns and less.

But still, if you are an above ground pool owner on a budget, this is a great deal. The Intex 28645EG Krystal Clear will pump water and still filter it to keep your pool water fresh and clean always.

It boasts a 21’’ tank that can handle an average of 15,000 gallons and still manage a reasonable turnover.

Regarding cleaning performance, there’s no doubt that this is a top performer, just like all the other Hayward products.

But then, compared to something like the C900 SwimClear Plus, its performance is relatively low considering this is a sand filter – filters down to 20 – 40 microns whereas the latter filters down to 10 – 15 microns. Though it may seem quite expensive, it is value for money considering there are no replacement costs – may be after 5 – 7 years when the sand has to be replaced.

But still, it is a great choice if you want something that is easy to maintain.

But remember, while it may look cheaper to maintain this filter, it will really cost you when it comes to backwashing; you need to refill the pool and add chemicals again. Another thing, it may not be able to filter those fine particles so achieving 100% clean water is not possible.

View on Amazon The S244T ProSeries is quite similar to the S210T ProSeries only that the former has been designed for much larger pools, evident from the larger 24’’ tank. Though it is quite expensive than the S210T ProSeries, I would advise you to buy this filter instead of the smaller one as a bigger sand filter is always better, unlike with pool pumps.

It will also filter down to 20 -40 microns and has a better turnover now that the filtration area is larger. This means it has been built for large pools and even though the tank size recommends 20,000 – 30,000 gallons, we tested it with 33,000 gallons in-ground pool and it didn’t disappoint. But then, we don’t recommend using it on such a large pool as the turnover will be less than two cycles a day. If you have over 30,000 gallons, I would recommend the same model but with a larger tank; maybe the Hayward S270T ProSeries with a 27” tank would work.

But on the downside, you will still have to deal with the cons of sand filters; i.e backwashing and lesser filtration efficiency compared to cartridge filters. On top of that, the water is not evenly distributed on the sand. Many are times I have found dirt settled in some areas. Ordinarily, you expect the dirt to be evenly distributed on the sand bed.

The Best Cartridge Filters

Sand filters don’t filter the smallest particles and so you may need a filter that is more efficient. That’s a cartridge filter. These are my favorite because their efficiency is better; 10 – 15 microns while sand does 20 – 40 microns. However, maintenance is costly and intensive.

View on AmazonTo be honest with you, the Intex 28633E Cartridge Filter is a better choice for above ground pools than the sand filter counterpart, Intex 28645EG Sand Filter.

This is because of one reason; sand filters need high-pressure pumps and the 28645EG. But this is not to mean that this filter pump has high pressure, the thing is, cartridge filters work efficiently even with low pressure.

This purchase is also a great deal and value for money; the initial cost is less than $100 and will pump and filter water simultaneously – talk of killing two birds with one stone.

But the best thing about this filter is the efficiency. Cartridge filters will capture particles as small as 10 microns so if you are wary of Recreational Water Illnesses, this will be a better purchase.

But on the downside, this pool filter requires frequent maintenance; typically, filter replacement every season. While it may be easier to replace the filter, it is quite costly. That said, you’d want to think twice if you are attracted to this filter because it retails at $83 – yes the initial cost is low but maintenance is high. But then, it’s not such a bother considering a sand filter will also increase your water bills.

View on Amazon The C900 works exactly like the Krystal Clear only that it has a larger filtration area. At 90 ft2, SwimClear Plus can turn over more water and thus it’s ideal for medium sized pools.

I like its performance; it’s far much better than what its sand competitor, the Hayward S210T ProSeries, does.

You also don’t have to worry about the local regulations and the impact of backwashing as you are only required to change the filter.

Though many find the maintenance of this filter very expensive, it is not as expensive as said. Sit down and do the math of refilling the pool and adding chemicals after backwashing. You will realize that it’s, in fact, cheaper and offers more value for money because it filters down to 10 – 15 microns while ProSeries will filter 20 – 40 microns.

One unique thing I like about this filter is the design; it stands quite high so you don’t have to bend and also, the pressure gauge and air relief are conveniently positioned at the top for easy accessibility.

But on the downside, you will need a much more powerful pump for it to work efficiently. I know many of the pool owners who buy this filter have medium sized pools and light duty pumps. The inefficiency lowers GPH which in turn slows the turnover.

View on AmazonThe C2030 is built for large pools and most commercial pools have it. It boasts a large 225 ft2 filtration area and would turn over a 20,000 gallons pool in no time.

Actually, I always recommend this if your swimming pool season is busy. Nothing sucks like the sun going down when you are waiting for the filter to finish the cycle.

With a high-performance pump, you are guaranteed the best filtration with all the debris, large and small, filtered out. I like the head design; very easy to open when cleaning or changing the cartridge. The material quality is also awesome and will withstand the scorching sun all year round. But if you can design a makeshift shade for it, or rather a cover, it would be best.

But on the downside, I wish the integral drain was much bigger, at least 2 inches. The 1.5- inch may be okay for a medium-size filter like the C900’s but for a heavy duty filter like this one, a 2-inch would make it faster. Otherwise, everything else is excellent, and so is the price too.

Pool Filters Buying Guide

In this section, we will now talk at length about important aspects that should be on your mind when buying pool filters. Remember, just like when buying the pool itself as well as the pump, there are those major considerations that made you decide on the pool you have or the pump you have installed.

To start off, let’s first look at the types of pool filters available and the features they offer.

Types of pool filters

If you did your homework, you understand that there are three types of pool filters. They are classified solely based on the type of media used. For starters, the media is what filters out the dirt from your pool water.

So, without wasting much time, let’s get down to business.

Sand Filters

A sand filter has a tank that is filled with special grade sand to filter dirt and debris. In this filter system, dirty pool water is passed through #20 US grade silica sand and as it flows through, dirt and debris are trapped inside leaving you with clean water at the bottom.

Sand filtration is the oldest filtration method and even though we have other pool filtration solutions, it is still a favorite. It filters down to 20 – 40 microns and the performance improves as it continues to trap more dirt.

The good thing about sand filters is that they are cheap and have a longer lifespan. A 50 lbs. bag of sand media will cost you $20 – $30 while a single cartridge filter will cost you an average of $50. By the time you will be required to change the sand filter media, let’s say 5 years, you will have bought around five cartridge replacements.

But on the downside, sand filters have two disadvantages. First, if your pump pressure is low, it becomes inefficient and the turnover is often longer. Another thing, backwashing may have restrictions and also, it wastes a lot of water. Actually, backwashing is a hot topic especially with the effect of Chlorine and DE in the expelled pool water.

Cartridge Filters

In this type of filter, the sand media is replaced by a filter cartridge; made from pleated polyester, the same one that your vehicle air cleaner uses.

Cartridge filters are better in efficiency compared to sand because they filter down to 10 – 15 microns. This will capture a lot of small; particles that a sand filter wouldn’t. For amateurs, cartridge filters are also the best because they are easier to install.

Unlike sand and DE filters, they have no multiport valves that means the plumbing system is straightforward. That also means a cartridge filter doesn’t have backwashing so, you won’t have to worry about local regulations or water wastage.

So, what’s done instead?

Cartridge filters require frequent cleaning and replacement. If you live in areas with lots of foliage, maintaining a cartridge filter will be quite a hassle. You are required to remove the filter and clean the large debris. If you have a busy schedule, finding time to do all these may be hard so a sand filter sounds a better option now that backwashing is just easy.Another thing, the lifespan of a cartridge filter is very short and to make matters worse, they are expensive.

DE Filters

Diatomaceous Earth filters are very similar to sand filters only that the media used here is DE. There are two types of DE filters; vertical grid filters and regenerative filters. Regardless of the structural difference of regenerative vs grid filters, the most important aspect of our discussion today is that they are both filled with DE as the filter media.

DE filters are the best when it comes to the efficiency of filtration. Unlike sand and cartridge filters, DE filters will filter down to 2 – 3 microns. This guarantees you that all the dirt and debris will be filtered out. If there are many cases of RWI, and you want to fully protect your family from exposure to pool dirt that carries these RWIs, it’s best to use a DE filter.

But then, why are DE filters not as popular as sand filters and cartridge filters?
First, they are very expensive compared to cartridge and sand. This is both in terms of initial cost and maintenance. But the worst bit is in maintenance as it requires backwashing just like sand and to add salt to the injury, it flushes out the DE so you have to replace DE after every filter backwash. Also, in some states, it is illegal to run a DE pool filter if you don’t have a separator tank to remove DE from the water you are allowing into the drain.

Is a Pool Filter Really Important?

All the hassles of maintaining your pool may be overwhelming and at some point, you may ask yourself, is a pool filter really important? What would happen if you don’t clean or replace your filter?

I like to give pool owners the example of their own kidneys. We all understand the role of the kidney in the body; to filter out those toxic substances. This ensures the body remains fresh with only the needed substances. This is the same case with your pool. The filter makes sure that all water contaminants are filtered out. This ensures your water is free from any harmful substances that may cause RWIs and other undesirable effects to swimmers.

Besides filtering out harmful dirt and debris, a filter will help keep water moving. This will prevent any possibility of insects breeding in your water. On top of that, it helps prolong the life of your pool. Lastly, pool filters, in some areas, are a requirement by law so you need to have one or else risk prosecution.

Actually, if you want to extend the life of your pool, you should take great care of your filter. Personally, I have ever ignored replacing my filter cartridge and it wasn’t long before my pump started developing problems. It is just like your body when you don’t take care of your kidneys, your body will start getting poisoned slowly.

Selecting the Right Sand Pool Filter Replacement

To get the best sparkling pool water, there is a threshold that needs to be met; filtration, sanitation, and filtration. A lot of problems with the filtration system attributes to most of the water problems I have experienced.

In my years of experience is pool servicing and maintenance, the first suspect once we diagnosed the filter to be the problem is ascertaining the size. Many pool owners buy the wrong sand pool filter size and this leads to some imbalance and thus the threshold is not met.

To help you shop the right sand filter size, here is a guidelines chart.

Tank size

Pool capacity

12’’ – 16’’ tank

3,000 – 8,000 gallons

16’’ – 20’’ tank

12,000 – 18,000 gallons

21”- 24” tank

18, 000 – 24000 gallons

24”- 30” tank

24,000 - 30,000 gallons

30”- 36” tank

30,000 - 50,000 gallons

Selecting the Right Cartridge Pool Filter Replacement

Just like in sand filters, pool owners also ignore the sizing of the filter.

While sand filters are calibrated depending on the size, cartridge filters are categorized based on the effective filtration area size.

Different pool filters have cartridges with varying sizes. What must be on your mind here is that the size of the filter should be proportionate to the size of the pool. This means, the larger the pool, the larger the filter is required to average the normal 8 – 10 hours turnover. If you find that your turnover is longer than expected, make sure you are using the right filter.

Here is a cartridge filter size guide. Please note, we have ranked some of the popular sizes and the number of gallons they can turn over in 8 and 10 hours.

Effective filtration area

Flow rate

8 hours

10 hours

25 ft2

25 GPM

12,000 gallons

15,000 gallons

50 ft2

50 GPM

24,000 gallons

30,000 gallons

75 ft2

75 GPM

36,000 gallons

45,000 gallons

90 ft2

90 GPM

44,000 gallons

54,000 gallons

120 ft2

120 GPM

58, 000 gallons

72,000 gallons

175 ft2

120 GPM

62,000 gallons

78,000 gallons

225 ft2

150 GPM

70,000 gallons

88,000 gallons

I know this might not give you the exact filter size you want but then, to have a rough idea of what filter size you require, there is a little arithmetic you need to work out.
Divide the turnover in gallons by the number of hours.

Example; 12,000 gallons ÷ 8 hours = 1500 gallons

This is the approximate size of the pool that should work with a 25 ft2 but then, it’s always a clever idea to oversize your pool cartridge filter. This will boost the turnover and shorten the running time of your pump thus saving energy.

Changing from Sand Filter to Cartridge Filter

Time and again, I stumble upon this question and in most cases, it goes unanswered or it is answered unsatisfactorily. For some reason, you may want to change from a sand filter to cartridge or vice versa.

Maybe you find it hard to replace your cartridge system or in an opposite case, you may want a better and more detailed filter system that can filter particles less than 20 microns, that is a cartridge filter.

From experience, I will tell you that it is very possible and in fact, you can do it yourself if you have basic plumbing skills. But for amateurs, it’s better if you call in professional service.

Filter backwashing

Since I joined the pool industry, there has been a lot of debate around filter backwashing and today, there are states that have strict backwashing rules.

So, what exactly is filter backwashing and are there any risks as stipulated by environmental bodies and advocates?

Filter backwashing is flushing out dirt that has accumulated in the sand or DE media. The pool is reversed to flush out only the trapped dirt particles leaving the sand or DE media intact. The first problem with backwashing it that it destabilizes the chemical levels of your pool water; Remember, the backwashed water is the same treated pool water. That said, you will be using more chemicals to maintain your pool.

But the worst thing about filter backwashing is the impact of the procedure on the environment. The chemicals used to treat pool water, or any other dirt that may have accumulated will get into the drain and end up being deposited elsewhere where it could risk marine life. It has been documented that high chlorine levels above 5.0 ppm can kill freshwater fish while DE can choke the oxygen in the water of a small stream.

To curb the impact of backwashing, local authorities and environmentalists have come up with laws and regulations regarding backwashing. There are some that are fronted by water conservationists as backwashing wastes a lot of water while the majority of the work is done by environmentalist. There are places where backwashing is prohibited while in other areas, it is controlled.

From experience, I will tell you that there are dozens of swimming pool laws and regulations that are flouted unknowingly. The 1989 Prevention of Pollution Act states that “No person shall cause or permit the occurrence of pollution, or cause or permit a risk of pollution to arise.” While you may think of acts like oil spillage and other gross examples of pollution, just backwashing a salt water system amounts to pollution; whether a residential pool or commercial.

I know by now you might have freaked out as no one wants to brush shoulders with the law. If you don’t want the hassles of documentation and all that, you can opt for cartridge filters. With these filters, backwashing is not required; just clean the filter manually or replace it when it’s worn out.

How to Clean a Sand Filter (Filter Backwashing)

Though backwashing looks like something very bad, it is the only way to clean a sand filter. You have no choice and in fact, you can do it and still conserve the environment. When it’s time to backwash your filter, you have to do it the right way.

There are two types of sand filters classified depending on the type of valve. We have multiport valves and slide valves and each has a different backwashing procedure.

To backwash, a sand filter with a multiport valve, shut off the pump and press down on the valve handle rotating it from FILTER to BACKWASH. Then, open the air bleeder assembly that’s located on top of the filter. Make sure the backwash hose is rolled out and any waste line valves opened. Now, turn the pump on and monitor backwash pressure spikes and also watch out for any hose kinking. Always be ready to shut off the pump in case you observe any of the two manifestations. Leave the pump running for a few minutes, maybe two or three depending on the pump pressure until the water is emptied. Then, switch off the pump and turn the multiport valve to RINSE and once again, put the pump on and run it for an average of 15 – 30 seconds to settle the sand bed. Once you are done, shut off the pump, move the adjustment to FILTER and note down the pressure.

When it comes to sliding valves, also known as push-pull valves, the procedure is quite different. But first, you will have to put off the pump before rolling out your backwash hose to where you are draining. Then, twist the plunger T-handle upward, two to three inches and open the bleeder assembly filter. After this, put the pump on and monitor the backpressure gauge and watch out for hose kinks. Always be ready to shut off the pump in case backpressure exceeds 30 PSI or when you see kinks on the hose. You will then backwash the sand filter for 2 – 3 minutes for the sand bed to settle and then, put the pump back on and remember to mark the pressure also.

How to Clean a Cartridge Filter

But how do you know that your cartridge is dirty or a replacement is required?The first suspect will be a surge in pressure. Always monitor your gauges and check out for spikes which are often indicators of dirty cartridges. Remove the cartridge, and clean it. If the cartridge was dirty, the problem of spiking pressure shouldn’t occur, at least in a while. But when it occurs again, maybe it’s time to replace your cartridge. But just before that, you’d want to try a deeper cleaning by soaking the filter in a cleaning agent like Leisure Time O Filter Clean Cartridge Cleaner. If that fails then you have a go ahead of buying a new cartridge.

Apart from pressure, you can also choose to manually inspect the cartridge. There are a few indicators that will tell you it is time to change your filter. The first thing will be the end caps. With your bare eyes, you may decide whether you need to replace it or not. Look for cracks and any signs of brittleness and if you are not sure whether it’s worn out or not, move to the inner parts, actually, the cartridge itself. Check the condition of the pleats; the Remar material should be firm and every piece intact. Any tatters, frays, and rips is a clear indication that you need to get a new cartridge.

It is always important to check the condition of the cartridge not only in light of the filtration efficiency but also to keep your pool safe. The cartridge may become brittles and the cracked end parts may be pumped to the system and damage other installations.

Sand vs Cartridge Filters Comparison

Now, it’s time we put the two filter options head-on to see how they square out. We will be discussing them with regards to the important aspects you need to consider when buying filters, i.e media, efficiency, and maintenance.

Media

When it comes to pool filtration, the media refers to the content of the filter; in other words, what filters the dirt. We won’t dwell here so much because this is straightforward. A sand filter has sand as the media while cartridge filters use a cartridge to filter the dirt and so is the case with DE.

But just to note, DE is the best as it filters down to 2 – 3 microns while cartridge and sand filters come second and last filtering down to 10 – 15 microns and 20 – 40 microns respectively.

I won’t say yet what the best media is because there are a lot of other factors that should inform your decision.

Efficiency

I know this is an interesting topic that you have been waiting. Just which filter will leave your pool water sparkling clean? For starters, there are several factors that determine efficiency and to put you in the best position, we are going to analyze the efficiency of cartridge filters vs sand filters vs DE filters.

Sand filters are not the best when it comes to efficiency but then, they are still relevant to large pool owners.

It is well understood that sand filters particles from 20 – 40 microns; so what’s the cause of the variation? Normally, when the sand filter is new, it will filter down to 40 microns but as more debris gets trapped in the sand bed, it improves efficiency and filters down to 20 microns. Unfortunately, at this stage, it becomes inefficient and will require backwashing or replacement.

One thing no one will tell you is that sand filters require high-pressure pumps. That said, you’d want to question their efficiency despite the fact that they filter much smaller particles.

On the other hand, cartridge filters are much better and are best if you want the best filtration.
It can filter down to 10 microns when at optimal performance. They also have a larger filtration area that makes it more efficient than sand filters. But then, it is important to note that there are different cartridge sizes; ranging from small to large. The most important thing here is to know that the larger the filtration area, the better the performance. That’s why the 225 sq. ft. Hayward C2030 SwimClear is a better option for large pools compared to the lesser 90 sq. ft. Hayward C900 SwimClear.

Verdict – Cartridge filters are the best as far as efficiency goes. They can filter much smaller particles that sand filters would miss out. They will also work even with low-pressure pumps.

Tip: A slightly dirty cartridge works best than a clean cartridge because the dirt helps to trap more dirt. So, cleaning your filter more frequently doesn’t boost efficiency!

Maintenance

You will agree with me that hiring a pool maintenance company is quite expensive. That said, you want a pool filter with minimal maintenance requirements. A lot of reviews I see emphasize that sand filters are easy to maintain meaning cartridge filters require maintenance.Today, I will tell you something different; both sand and cartridge filters require intensive maintenance. The idea is to choose one that will be easier for you and convenient.

When it comes to cartridge filters, a lot of people will hate on the basis of the frequency of cartridge cleaning and the expensive cost of replacement. It is true that your cartridge needs to be replaced more often, and at a cost too. If not, you need to at least clean it manually. This may be quite cumbersome and overwhelming if you have a busy schedule.

On the other hand, sand filters are hyped as maintenance free but from today, forget that myth, here are the facts.

When it comes to media replacement, I agree that sand filters are the best; replacement is after 5 – 10 years. This is where the conversation ends and thus the misconception that sand filters are maintenance free. From time to time, depending on the usage, sand filters require cleaning and unlike cartridge filters that are removed and cleaned manually, you will only need to backwash sand filters. While it may be very easy to backwash the filter, the impact is gross. You will need to top up the water (the capacity of your pool, 2000 gallons, 5000 gallons, e.t.c.) that’s a higher water bill and again, chemicals need to be added in the new water. For cartridge filters, you only need around 20 gallons and your garden hose.

Our Verdict: Sand Filter vs Cartridge Filter

So, what’s the best filter system for you?

To be honest, this is a matter of preference and in some cases, you don’t even have a choice because of local laws and regulations. Your pump could also determine the type of filter you have; say you buy the Krystal Clear that combines.

But a few things to note; if you have a low-pressure pump, avoid sand filters as they become inefficient when a little dirt builds up. For the best and most efficient filtration, DE is the best media but due to its unpopularity, cartridge filters fill in the gap and are much cheaper.

Enough said it’s my time to check out. I wish you the best as you continue shopping for a pool filter so until next time, have a wonderful swimming season.